Furnace charging



Jan. KERNOHAN ET AL.

FURNACE CHARGING Filed Nov. 8 1.922

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Jan. 1, 1924 R. B. KERNOHAN ET AL.

FURNACE CHARGING Filed Nov. 8 1.922 5 Sheets-Sheet 5 WITNESSES reamed Jan. 1,1924. 1

UNITED STATES 1,419,507 PATENT OFFICE.

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To all 'wlwm cmwem:

Be it known that' we, ROBERT B. Knnno- HAN and MORGAN HALL, residing at Pittsbur h, in the -county of Alleghen and State of Ieunsylvania, citizensof the nited States, have invented or discovered certain new and useful Improvements in Furnace Charging, of which improvements thefollowing is a specification. I 4

Our invention relates to means for charging material into furnaces, and finds particular value when embodied in what we term a dolomite gun. An open-hearth steel furnace is lined with mineral substance, ordinarily a mixture of spec fic minerals, among which is dolomite, with which the furnace charge reacts. Reaction takes place chiefly along the margin. of the pool of molten charge as its lies in-the furnace, and according y the consumption of the lining material ismost rapid, the erosion is reatest, along that marginal line. It folFows from this that in furnace operation it is desirable to replenish the supply of Application filed November 8, 1922. Serial No. 599,347.

this material from a gun toits place on-the furnace hearth, but the roposal has not overcome the difliculties a1 uded to, that the more finely divided particles of the injected material are swept awa b i the -flame, and lost in the bath and lo ged in the regenerators, while-the coarser particles when they reach their restin place, do not themselves afford a suflicient y dense mass; and, in addition, it has been necessary to advance the muzzle of the gun into the furnace chamber and to a point adjacent the resting place for the material, and consequently there. are difficulties incident to exposure of the appara tus to the heat of the furnace.

Our invention is found in a gun which projects the material in coherent units or charges which are not subject to deterioration in projection, and a gun which need not enter the furnace chamber.

. The invention is illustrated in the accompan ing drawings. Fig. Iis-a view in vertica and transverse section through an open hearth furnace, and showing in side elevalining mineral, particularly along the mar-g,.tion and in operative relative osition adgin of the pool.

This is commonl done by manual labor. The doors of the irnace are opened fromtime to-time, while furnace operation progresses, and attendants shovel the material, and throw it to the place desired. The work is arduous, the conditions under which it is done are most difiicult to endure, and at best there is an element of inaccuracy in the placement of the material. Furthermore,

' the loose and more or less finely divided material so hurled acrossthe furnace chamber meets the sweep of the gases of combustion, and the finer (particles are in greater or less degree'carrie away on the stream of gases, and this with undesirable consequences: first, the material as it reachesits restin place on the back wall of the furnace, ing deprived of an appreciable part of its finer ingredients, does not consolidate as it should, and is therefore too rapidly consumed and wasted; and, second, the material carried on the stream of hot ases isin part deposited on the surface of t e bath, where its desired good effect is substantially lost, and in part carried 'beyond the furnace chamber and deposited'in the checkwork of the regenerators, where it accumulates with manifest prejudice to furnace operation and maintenance.

It has already been proposed to shoot jacent the furnace, the n in w ich our invention resides. The s owing of Fig. I is' diagrammatic. Fig. II is a similar view, but to larger scale, in which the showing of the furnace is but fragmentary, while the more minute structure of the gun is elaborated. Fig. III is a view in section of a detail, the plane of section bein indicated by the line III III, Fig. II. %ig. IV is a'fragmentary view, illustrating a variation in the preparation of the material for introduction into and pro'ection from the gun. Figs. V and VI are rawn to still larger scale, and together constitute a View in vertical and longitudinal section of a gun differin in detail from that of Figs. I- III.

Re erring first to Fig. I, the furnace is indicated at 1. Its hearth 2 is forined of The gun will in any case be mounted in,

such mannerthat it may be moved about and brought to position opposite one or another furnace door, as may be desired. In the actual installation we are describin tracks 5 are laid along the mill floor longitudinally of the furnace, and upon these ltl till

tracks a truck 6 is mounted to travel, which truck carries the gun. The arrangement is such that, as the car is moved along thetracks, the gun is advanced in position and brought opposite one or another of the doors 3 of the furnace.

Tn this Fig. l the dotted lines (it-a indicate the trajectory of the material shot from the gun, and it will be observed that the material so shot will come to rest on what is called the back wall of the furnace, more specifically, on the hearth at the remote margin of the molten pool which constitutes the furnace charge.

Turning from Fig. l to Fig ll, we come to more minute features of structure. The gun is here shown to be mounted upon the truck 6, through a vertical swivel 8 and a horizontal swivel 9, to the end that the gun may be aimed, and that the shot-in material may be placed on the back wall of the furnace high or low, to right onto left, as may be desired.

The truck 6 carries a tank 10 which, in operation, will be understood to be filled with air under compression. The truck may also carry a motor and a pump for compressing air, but since these features form no necessary part of our invention, they are not shown. From the tank 10 there is pneumatic communication to the barrel of the un, to which in Fig. llll the numeral 4 is immediately applied, and at the breech end thereof. This communication is controlled by a valve 11 operable manually, as is indicated. The port controlled by the valve is a port of large capacity, and the valve is adapted to be opened immediately to the full. Immediately to rearward of the gun barrel proper 4 is a loading chamber 16. This chamber is provided with a receiving hopper 12. Theopening through the hopper into the loading chamber is controlledby gates 13 held normally closed by a spring 14, and these gates, when closed, form a substantially tight joint. The pneumatic communication which has already been mentioned is immediate to this loading chamber and through it to the barrel at the breech end. A pusher 17 is provided operable manually from the outside to advance a charge when once it has been introduced from the loading chamber into the gun barrel at the breech end.

A screen 15 may be provided to protect the attendant from the heat of or from the light of the furnace.

In Fig. Til the charge which is shot by the gun into the furnace is indicated in two successive positions, at b and at c. The chargeconsists of the desired material in proper physical condition, held within a container adequate to efi'ect the ends already indicated. The container is essenis shown within the and tied at the aerator tially cylindrical in shape and is of such size that being filled, it will snugly fill the barrel of the gun'and pass, under the pneumatic pressure provided, through the barrel and be projected from. the muzzle with suitable force.

, We have found that a paper bag constitutes an adequate container and, as in indicated in Figure ll, this paper ban is formed with both ends gathered and tied. Paper Y bags ordinarily available are rectangular at the bottom. By using a bag which is gathered and tied at both ends we make a package or charge which is truly cylindrical. The paper employed will be of sufficient toughness and resistance to hold tother when the charge is fired and to hold the charge as it passes through the gaseous stream and across the furnace chamber to its place of lodging, where the paper container will be broken by impact and the paper will be burned, but not before it has served its purpose. lts consumption will have no appreciable effect upon the steelprocess. 1

lln igure IV we have indicated an alternative form for the container. Here barrel 4 of the It is gathered At the n a filled container d.

forward end.

Kill

rear end it is closed in the manner usual in paper bag making, but has secured to it a cup e which ordinarily will be made of paper also. This cup is so positioned that it flares rearwardly and is of such shape and size that its side walls closely engage the bore of the barrel 4:.

The gates 13 close behind the package as it is introduced. When the package has come to the position shown at b in the loading chamber, the pusher 17 is advanced, and so the package is carriedforward into the barrel of the gun proper in the position indicated at 0, 0r it'may be advanced until it lies wholly within the bore. As has been explained, it is so proportioned that it fits snugly within the bore. If the package be formed, as is particularly illustrated in Figure TV, it is desirable that the package be so far advanced into the bore that the walls of the cup 6 will bear upon the walls of the bore.

Operation will readily be understood. The material to be placed in the furnace is taken and made 'up into a packa e as described. The package is intro uced through the hopper 12, the gates 13 swing- 7 ing aside, and comes to place in the loading chamber. It is then advanced by means of the usher until it is entered into the bore of the gun. The valve 11 may then, be thrown wide open. The sudden rush of compressed air from tank 10 fills all thespace to rearward of the package or charge 6 and drives it through the barrel 4L and ejects it with sufficient force to carry it to its intended place. Of course, the gun will initially have been aimed, and the attendant will by experience known how to aim it, in order to brin the material to rest at the desired point. [518 material of which the container is formed, in this instance paper, is such that immediately on impact it will be destroyed, either by bursting or by burning or by both, and it will be such as to have no disturbing effect upon normal furnace operation.

The modification illustrated in Figs. V and VI will not require labored description. The barrel of the gun is here marked 24, the

muzzle end of it is shown in Fig. V and the breech end in Fig. VI. ,Within this barrel and upon a central stem 27 a scoop 25 with hollow stem 26 reciprocates telescopically. The stem 26 at its rear end is enlarged to form a piston 31. This piston is held by a trigger 28 at the rear limit of reciprocation until the time for firing comes. A suitable hopper 30 forms an opening through which access is had tothe scoop 25 when the scoop is retracted for the purpose of charging.

The parts bein Figs. V and container, which as alreadyhas been said is preferably a paper bag, is deposited in scoop in the position shown in 25. It is of such size and shape that, when placed in the scoop, the loaded scoop will advance freel through the barrel of the gun. When t e scoop has been loaded and compressed air has been admitted to the breech end of the barrel of the gun to rearward of piston 31, the trigger 28 is tripped (as is done by the swinging of the hand lever 29), the piston is driven to the left (as seen in Figure VI), and the laden scoop is thrust muzzleward to the limit of its range of movement. The charge which it carries is under acquired momentum projected from the muzzle of the gun, to efiect the end described.

The packaging of the material overcomes the difliculties described above, attendant on manual operation; furthermore, in so aggregating the material in coherent units, nicely I, the material within its shaped to and filling the bore of the gun (Fig. '11), it becomes possible to shoot them to much greater distances'than has been possible with guns shooting loose material. In-

cplnsequence, it is not necessary to advance t e through the door and into the furnace chamber, and the difliculties otherwise to be overcome in protecting the gun from high temperature are avoided.

I As is intimated at the beginning of this specification, the apparatus here particularly described as a dolomite gun, for projecting into an open hearth furnace charges of material for repair and maintenance of the furnace lining, is applicable generally for projecting desired material. to partlcular points within a furnace chamber.

We claim as our invention:

1. The method herein described of replenishing a furnace lining which consists in projecting lining material across the furnace chamber in aggregated units inaccessible to the stream of gas through which-they are projected. i

2. A rojectile adapted to be used in the replenis ment of furnace linings which consists of a'quantity of lining material in an aggregated unit inaccessible to the stream of gas through which it in service is projected, substantiall as described.

gun and cause its muzzle to project 3. A. ro ectile adapted to be used in the replenis ment of furnace lining which consists of a quantity of lining material enclosed within a destructible container.

4. A projectile adapted to be fired from a pneumatic gun into a furnace chamber, said projectile consisting ofa quantity of loose mineral held within a destructible container, said container being provided posteriorly with-a rearwardly flaring cup adapted to en- 

